JP5314712B2 - Base station apparatus and user apparatus - Google Patents

Description

  The present invention relates to the technical field of mobile communication, and more particularly to a base station apparatus and a user apparatus in a mobile communication system using next-generation mobile communication technology.

  Wideband Code Division Multiplexing (WCDMA) method, high speed downlink packet access (HSDPA) method, high speed uplink packet access (HSUPA), etc. The succeeding communication system, that is, the Long Term Evolution (LTE) system, has been studied by the WCDMA standardization organization 3GPP and specification work is in progress.

  As a radio access scheme in the LTE scheme, an Orthogonal Frequency Division Multiplexing Access (OFDMA) scheme is defined for the downlink, and a single carrier frequency division multiple access (SC-FDMA) is used for the uplink. (Division Multiplexing Access) method is defined (for example, see Non-Patent Document 1).

  The OFDMA scheme is a multicarrier transmission scheme in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers) and data is transmitted on each subcarrier.

  According to the OFDMA system, high-speed transmission can be realized by arranging the subcarriers densely while being orthogonal to each other on the frequency axis, and it can be expected that the frequency utilization efficiency is improved.

  The SC-FDMA scheme is a single carrier transmission scheme in which a frequency band is divided for each user equipment UE (User Equipment), and transmission is performed using different frequency bands among a plurality of user apparatuses UE.

  According to the SC-FDMA scheme, the interference between the user equipment UEs can be reduced easily and effectively, and also the transmission power fluctuations can be reduced. Therefore, the SC-FDMA scheme reduces the consumption of the user equipment UE. It is preferable from the viewpoint of power generation and coverage expansion.

  In the LTE scheme, communication is performed by allocating one or more resource blocks (RB: Resource Block) to the user apparatus UE in both downlink and uplink.

  The base station apparatus eNB decides which user apparatus UE to allocate resource blocks among a plurality of user apparatuses UE every subframe (1 ms in the LTE scheme) (this process is “scheduling”). be called).

  In the downlink, the base station apparatus eNB is configured to transmit a downlink data signal using one or more resource blocks to the user apparatus UE selected by scheduling.

  Also, in the uplink, the user apparatus UE selected by scheduling transmits an uplink data signal to the base station apparatus eNB using one or more resource blocks.

  The uplink data signal is transmitted via a PUSCH (Physical Uplink Shared Channel, Physical Uplink Shared Channel), and the downlink data signal is transmitted through a PDSCH (Physical Downlink Shared Channel, Physical Downlink Shared Channel). Sent.

  Here, the uplink data signal may be referred to as a “PUSCH signal”, and the downlink data signal may be referred to as a “PDSCH signal”.

  In addition, as a communication method succeeding the LTE method, the LTE-Advanced method (LTE method after Release 10) has been studied by 3GPP (for example, see Non-Patent Document 2).

  In the LTE-Advanced scheme, it is agreed that “Carrier Aggregation” is performed as a requirement. Here, “Carrier Aggregation” means simultaneous communication using a plurality of carriers.

  For example, when “Carrier Aggregation” is performed in the uplink, a different carrier is used for each component carrier (component carrier, hereinafter referred to as CC). Therefore, the user apparatus UE uses a plurality of carriers to generate an uplink signal (that is, An uplink data signal and an uplink control signal).

  Also, when “Carrier Aggregation” is performed in the downlink, since different carriers are used for each CC, the base station apparatus eNB uses a plurality of carriers to generate downlink signals (that is, downlink data signals and downlinks). Link control signal).

  In the uplink of the LTE scheme, as described above, since the single carrier transmission scheme is used, uplink signals are transmitted in a continuous frequency band.

  On the other hand, in the LTE-Advanced uplink, it is considered that uplink signals are transmitted in a discontinuous frequency band in the following cases.

<Case 1>
When “Carrier Aggregation” is performed, an uplink data signal is transmitted using a different CC.

<Case 2>
When “Carrier Aggregation” is performed, an uplink data signal and an uplink control signal are transmitted in different CCs.

  Note that the uplink control signal is a signal transmitted via a PUCCH (Physical Uplink Control Channel, Physical Uplink Control Channel), and may be referred to as a “PUCCH signal”.

<Case 3>
An uplink data signal is transmitted in a discontinuous (ie, discrete) frequency band within a single carrier.

<Case 4>
An uplink data signal and an uplink control signal are transmitted in a discontinuous frequency band within a single carrier.

  As in case 1 or case 3 described above, by transmitting an uplink data signal in a discontinuous (that is, discrete) frequency band, more flexible frequency band allocation is possible, and communication in the uplink is possible. Efficiency can be improved.

  That is, in general, there are high-quality frequency bands and bad-quality frequency bands due to the influence of Fading, etc., but when discontinuous frequency bands are allocated, the quality bands are good as the frequency bands for transmitting uplink signals. Since it is possible to select and assign a frequency band, it is possible to improve communication efficiency in the uplink.

  Conversely, when only continuous frequency band allocation is performed, it is difficult to select and allocate such a high-quality frequency band, so compared with the case where discrete frequency band allocation is performed. Therefore, the communication efficiency in the uplink is not improved.

  Further, as in the case 2 or case 4 described above, by transmitting the uplink data signal and the uplink control signal in the discontinuous frequency band, the uplink control signal to be transmitted via the PUCCH via the PUSCH. It is possible to avoid the process of transmitting or the process of stopping the transmission of some signals.

  By the way, when an uplink signal is transmitted in the discontinuous frequency band described above, there is a problem that PAPR (Peak-to-Average Ratio) increases.

  When the PAPR increases, the user apparatus UE transmits an uplink signal in the nonlinear region of the power amplifier (power amplifier), and the amount of interference with the adjacent channel (adjacent frequency band) increases.

  In order to suppress an increase in the amount of interference with the adjacent channel, the user apparatus UE needs to be equipped with a highly linear power amplifier (power amplifier). However, the system increases the cost and size of the user apparatus UE. Overall, it is not preferable.

  Therefore, in order to avoid the influence of the increase in PAPR while avoiding the increase in cost and size of the user apparatus UE described above, it has been studied to reduce the maximum transmission power in the user apparatus UE. Reducing the maximum transmission power in this way is called “MPR (Maximum Power Reduction)” (see, for example, Non-Patent Document 3).

  The value of the MPR is determined based on the transmission bandwidth of each block, the frequency difference between the blocks, and the like when each of the assigned discontinuous frequency bands is called a “block”.

  Further, when the maximum transmission power is reduced in this way, there is a problem that uplink cell coverage is reduced, and therefore, in general, a necessary minimum value is defined as the MPR value.

  It is also under consideration to define a control signal for notifying whether or not the user apparatus UE has the ability to transmit an uplink signal in a discontinuous frequency band to the base station apparatus eNB.

  By defining such a control signal, the base station apparatus eNB can grasp that the user apparatus UE does not have an ability to transmit an uplink signal in a discontinuous frequency band. It is possible to assign a frequency band for transmitting an uplink data signal and an uplink control signal by a method suitable for the UE.

3GPP TS 36.211 (V9.1.0), “Physical Channels and Modulation”, May 2008 3GPP TS 36.913 (V8.0.1), “Requirement for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA) (LTE-Advanced)” 3GPP TS36.101 (V9.5.0), “E-UTRA UE radio transmission and reception”

  However, the above-described conventional mobile communication system has the following problems.

  The mobile terminal which is the user apparatus UE exists from a high function (High end) to a low function (Low end).

  Here, the high-function mobile terminal transmits the uplink signal in the allocated discontinuous frequency band while applying the above-described MPR and suppressing the decrease in the maximum transmission power of the uplink signal to the maximum. It is possible to improve the efficiency of communication in the uplink.

  On the other hand, a low-function mobile terminal, on the other hand, transmits uplink signals in the allocated discontinuous frequency band and does not support MPR associated therewith, thereby reducing the cost and complexity of the mobile terminal. It is possible.

  In such a case, the base station apparatus eNB needs to distinguish the above-described high-function mobile terminal from the low-function mobile terminal.

  Furthermore, the minimum amount of power reduction necessary to reduce the amount of interference with adjacent channels is defined as the MPR value described above.

  In such a case, when there is a frequency band to be protected in a frequency band adjacent to the frequency band for transmitting the uplink signal, it is necessary to define a larger MPR value.

  On the other hand, when there is no frequency band to be protected in the frequency band adjacent to the frequency band for transmitting the uplink signal, a smaller MPR value is defined.

  In addition, when it is necessary to define a larger MPR value, the MPR value is determined more complicatedly depending on the frequency band in which the uplink signal is actually transmitted in order to minimize the decrease in coverage. Control may apply.

  In such a case, as an operation of the user apparatus UE, for example, in order to simplify the processing to be implemented, the uplink in the discontinuous frequency band only in a place where there is no frequency band to be protected in the adjacent frequency band An operation that has the ability to transmit a signal and does not have the ability to transmit an uplink signal in a discontinuous frequency band only in a place where there is no frequency band to be protected in an adjacent frequency band is preferable. There is a case.

  However, as described above, when there is one control signal for notifying whether or not there is an ability to transmit an uplink signal in a discontinuous frequency band, the ability is changed according to the frequency band described above. Difficult to do.

  Therefore, the present invention has been made in view of the above-described problems, and transmits uplink signals in a discontinuous frequency band according to the capability of the user apparatus and the frequency band in which the user apparatus UE actually communicates. An object of the present invention is to provide a base station apparatus and a user apparatus that can determine whether or not to perform a frequency band assignment for transmitting an uplink signal based on the determination result.

  A first feature of the present invention is a base station apparatus that performs radio communication with a user apparatus in a mobile communication system, and is capable of simultaneously transmitting uplink signals in the allocated discontinuous frequency band from the user apparatus. And a receiving unit configured to receive a control signal for notifying whether or not the control signal is included, and the control signal is configured to be notified for each operation band.

  A second feature of the present invention is a user apparatus that wirelessly communicates with a base station apparatus in a mobile communication system, wherein uplink signals are simultaneously transmitted to the base station apparatus in an allocated discontinuous frequency band. A transmission unit configured to transmit a control signal notifying whether or not it has the capability to transmit, wherein the control signal is configured to be notified for each operation band; To do.

  As described above, according to the present invention, whether to transmit an uplink signal in a discontinuous frequency band is determined according to the capability of the user apparatus and the frequency band in which the user apparatus actually communicates. Based on the determination result, it is possible to provide a base station apparatus and a user apparatus that can assign a frequency band for transmitting an uplink signal.

It is a functional block diagram of the user apparatus UE which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of "the information which shows whether the user apparatus UE can transmit an uplink signal by a discrete frequency band" produced | generated by the user apparatus UE which concerns on the 1st Embodiment of this invention. is there. It is a functional block diagram of the base station apparatus eNB which concerns on the 1st Embodiment of this invention.

(Mobile communication system according to the first embodiment of the present invention)
Hereinafter, a mobile communication system according to a first embodiment of the present invention will be described with reference to the drawings. In all the drawings for explaining the present embodiment, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

  The mobile communication system according to the present embodiment is a system to which, for example, the LTE scheme or the LTE-Advanced scheme is applied.

  That is, the mobile communication system according to the present embodiment includes a base station apparatus eNB and a user apparatus UE that communicates with the base station apparatus eNB, and the base station apparatus eNB and the user apparatus UE may use the LTE scheme or the LTE-Advanced scheme. Use to communicate. The user apparatus UE may be called a mobile terminal.

  In the mobile communication system according to the present embodiment, when the LTE-Advanced scheme is applied, “Carrier Aggregation” may be applied, that is, communication using a plurality of CCs in uplink or downlink. Done.

  In the mobile communication system according to the present embodiment, when the LTE scheme is applied, communication using one CC is performed.

  Here, the CC corresponds to one system carrier in the LTE scheme. That is, in the LTE scheme, communication using one CC is performed, but in the LTE-Advanced scheme, communication using two or more CCs may be performed.

  In the mobile communication system according to the present embodiment, PDSCH and PDCCH (Physical Downlink Control Channel) shared and used by each user apparatus UE are used in the downlink.

  In the LTE scheme or the LTE-Advanced scheme, “Operating band (operating band)” is defined as a set of frequency bands to be operated (Chapter 5.5 of Non-Patent Document 3).

  As such “Operating band”, for example, “Band 1” that is “Operating band” of 2 GHz band, “Band 5” that is “Operating band” of 800 MHz band, and the like are defined.

  In general, the user apparatus UE notifies the base station apparatus eNB of “Operating band” supported by the own station. That is, the user apparatus UE generally has a capability of performing communication in one or two or more “Operating bands”, and the “Operating band” having the capability of performing such communication is transmitted to the base station apparatus. Notify eNB.

  Also, the base station apparatus eNB notifies the user apparatus UE in the area of the own station by using broadcast information about which “Operating band” the mobile communication service provided by the own station is provided.

  Note that CC belongs to one of “Operating band” since it corresponds to one system carrier of the LTE system.

  In the mobile communication system according to the present embodiment, downlink data signals (user data, that is, normal data signals) are transmitted via the PDSCH.

  Further, the user apparatus UE that performs communication using the ID of the user apparatus UE that performs communication using the PDSCH, the transport format information of the downlink data signal (that is, downlink scheduling information), and the PUSCH via the PDCCH. And the downlink control signal such as the transport format information (i.e., uplink scheduling grant) of the uplink data signal.

  The PDCCH may be referred to as a “downlink L1 / L2 control channel”. Further, “downlink scheduling information” and “uplink scheduling grant” may be collectively referred to as “downlink control information (DCI)”.

  In the mobile communication system according to the present embodiment, PUSCH and PUCCH that are shared and used by each user apparatus UE are used in the uplink.

  An uplink data signal (user data, that is, a normal data signal) is transmitted via the PUSCH.

  Also, downlink quality information (CQI: Channel Quality Indicator) for use in scheduling processing, adaptive modulation and coding processing (AMCS), and PDSCH delivery confirmation information related to PDSCH via PUCCH. (Acknowledgement Information) is transmitted.

  Such downlink quality information is called “CSI (Channel State Information)”, which is an indicator that summarizes “CQI”, “PMI (Pre-coding Matrix Indicator)” and “RI (Rank Indicator)”. May be.

  The contents of the acknowledgment information include an acknowledgment (ACK: Acknowledgment) indicating that the downlink signal has been properly received or a negative acknowledgment (NACK: Negative Acknowledgment) indicating that the downlink signal has not been properly received. ).

  As illustrated in FIG. 1, the user apparatus UE according to the present embodiment includes a capability signal generation unit 102, an uplink signal transmission unit 104, and a downlink signal reception unit 106.

  Note that the capability signal generation unit 102, the uplink signal transmission unit 104, and the downlink signal reception unit 106 are connected to each other.

  The capability signal generation unit 102 is configured to generate a capability signal for notifying the capability (ie, capability) of the user apparatus UE.

  Here, the Capability signal includes information that notifies whether or not the user apparatus UE can simultaneously transmit an uplink signal in a discrete frequency band (that is, a discontinuous frequency band).

  That is, if the capability signal generation unit 102 can simultaneously transmit uplink signals in discrete frequency bands, the user equipment UE can simultaneously transmit uplink signals in discrete frequency bands. If the information indicating whether or not is “1” and the user apparatus UE cannot simultaneously transmit an uplink signal in a discrete frequency band, the uplink signal may be simultaneously transmitted in a discrete frequency band. Information indicating whether or not it is possible may be configured to be “0”.

  Note that the information indicating whether or not uplink signals can be transmitted simultaneously in discrete frequency bands includes the case where uplink data signals are transmitted simultaneously in discrete frequency bands and in the discrete frequency bands. It may be set for each of the case where the uplink data signal and the uplink control signal are transmitted simultaneously.

  Further, the capability signal generation unit 102, as shown in FIG. 2, information indicating whether or not uplink signals can be simultaneously transmitted in discrete frequency bands for each frequency band supported by the user apparatus UE. It may be configured to generate a Capability signal including it.

  Here, the frequency band may be the above-described “Operating band (operating band)”. Such an “Operating band” may be called a “Frequency band”.

  That is, the user apparatus UE is configured to generate a Capability signal including information indicating whether or not uplink signals can be transmitted simultaneously in discrete frequency bands for each operation band supported by the user apparatus UE. It may be.

  In addition, this frequency band may be a frequency band more generally.

  In addition, when carrier aggregation is performed between the user apparatus UE and the base station apparatus eNB, an uplink signal is simultaneously transmitted in the above-described discrete frequency band to each carrier on which carrier aggregation is performed. Information indicating whether or not it can be sent may be notified.

  Alternatively, when carrier aggregation is performed between the user apparatus UE and the base station apparatus eNB, when a plurality of carriers when the carrier aggregation is performed belong to two or more operation bands, this 2 Information indicating whether or not uplink signals can be simultaneously transmitted in such discrete frequency bands may be notified to each of the two or more operation bands.

  Alternatively, when carrier aggregation is performed between the user apparatus UE and the base station apparatus eNB, and as described above, uplink signals are simultaneously transmitted in the discrete frequency bands to the respective operation bands. If information indicating whether or not it can be transmitted is uplinked simultaneously in a discrete frequency band based on the information related to the operation band to which a plurality of carriers belong when carrier aggregation is performed. It may be determined whether a signal can be transmitted.

  More specifically, only when it is notified that uplink signals can be transmitted simultaneously in a discrete frequency band with respect to all of the operation bands to which a plurality of carriers belong when carrier aggregation is performed. It may be determined that uplink signals can be transmitted simultaneously in different frequency bands.

  The uplink signal transmission unit 104 is configured to transmit an uplink data signal and an uplink control signal to the base station apparatus eNB via PUSCH and PUCCH.

  Note that the uplink signal transmission unit 104 is configured to transmit the capability signal generated by the capability signal generation unit 102 to the base station apparatus eNB.

  The downlink signal reception unit 106 is configured to receive a downlink data signal and a downlink control signal from the base station apparatus eNB via PDSCH and PDCCH.

  As illustrated in FIG. 3, the base station apparatus eNB according to the present embodiment includes a capability signal reception unit 202, an uplink signal reception unit 204, an uplink resource allocation unit 206, and a downlink signal transmission unit 208. To do.

  The uplink signal reception unit 204 is configured to receive an uplink data signal and an uplink control signal from the user apparatus UE via the PUSCH or PUCCH.

  The capability signal receiving unit 202 is configured to acquire a capability signal from the uplink signal received by the uplink signal receiving unit 204.

  As described above, the Capability signal includes information notifying whether or not the user apparatus UE can simultaneously transmit an uplink signal in a discrete frequency band (that is, a discontinuous frequency band). . Further, as described above, such information may be notified for each frequency band supported by the user apparatus UE.

  The downlink signal transmission unit 208 is configured to transmit a downlink data signal and a downlink control signal to the user apparatus UE via PDSCH and PDCCH.

  The uplink resource allocation unit 206 determines, for each subframe, a user apparatus UE to which the resource block is allocated among the plurality of user apparatuses UE, and transmits an uplink signal to the user apparatus UE. It is configured to allocate resource blocks.

  Specifically, the uplink resource allocation unit 206 determines whether or not to transmit an uplink signal in a discontinuous frequency band, based on the capability signal received by the capability signal reception unit 202, and the determination. Based on the result, it is configured to allocate a frequency band (resource block) for transmitting an uplink signal.

  That is, the uplink resource allocation unit 206 is notified that the user apparatus UE can transmit uplink signals simultaneously in discrete frequency bands (that is, discontinuous frequency bands). In other cases, resources are allocated in a continuous frequency band.

  According to the mobile communication system according to the first embodiment of the present invention, the base station apparatus eNB, based on the Capability signal acquired from the user apparatus UE, the capability of the user apparatus and the frequency band in which the user apparatus actually communicates In consideration of the above, it is possible to determine whether or not to transmit an uplink signal in a discontinuous frequency band, and to allocate a frequency band for transmitting an uplink signal based on the determination result.

  The characteristics of the present embodiment described above may be expressed as follows.

  A first feature of the present embodiment is a base station apparatus eNB that performs radio communication with a user apparatus UE in a mobile communication system, and simultaneously transmits uplink signals in a discontinuous frequency band allocated from the user apparatus UE. A Capability signal receiving unit 202 configured to receive a Capability signal (control signal) for notifying whether or not it has a transmission capability is provided, and the Capability signal is configured to be notified for each operating band. It is a summary.

  In the first feature of the present embodiment, the capability signal may be configured to notify whether or not the capability signal has the ability to transmit uplink data signals simultaneously in the allocated discontinuous frequency bands.

  In the first feature of the present embodiment, the capability signal is configured to notify whether or not it has an ability to simultaneously transmit an uplink data signal and an uplink control signal in the allocated discontinuous frequency band. May be.

  A second feature of the present embodiment is a user apparatus UE that wirelessly communicates with the base station apparatus eNB within the mobile communication system, and is simultaneously uplinked to the base station apparatus UE in a discontinuous frequency band assigned thereto. An uplink signal transmission unit 104 configured to transmit a capability signal for notifying whether or not it has a capability of transmitting a link signal is provided, and the capability signal is configured to be notified for each operation band. It is a summary.

  In the second feature of the present embodiment, the capability signal may be configured to notify whether or not the capability signal has the ability to transmit uplink data signals simultaneously in the allocated discontinuous frequency bands.

  In the second feature of the present embodiment, the capability signal is configured to notify whether or not it has an ability to simultaneously transmit an uplink data signal and an uplink control signal in the allocated discontinuous frequency band. May be.

  Note that the operations of the user apparatus 100 and the base station apparatus 200 described above may be implemented by hardware, may be implemented by a software module executed by a processor, or may be implemented by a combination of both. .

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the user apparatus 100 and the base station apparatus 200. Further, the storage medium and the processor may be provided in the user apparatus 100 and the base station apparatus 200 as discrete components.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

DESCRIPTION OF SYMBOLS 100 ... User apparatus 102 ... Capability signal generation part 104 ... Uplink signal transmission part 106 ... Downlink signal reception part 200 ... Base station apparatus 202 ... Capability signal reception part 204 ... Uplink signal reception part 206 ... Uplink resource allocation part 208 ... Downlink signal transmitter

Claims (6)

In a mobile communication system, a base station device that wirelessly communicates with a user device,
A receiving unit configured to receive a control signal for notifying whether or not the user apparatus has an ability to simultaneously transmit an uplink signal in an allocated discontinuous frequency band;
The base station apparatus, wherein the control signal is configured to be notified for each operation band.   The base station according to claim 1, wherein the control signal is configured to notify whether or not the control signal has an ability to transmit uplink data signals simultaneously in the allocated discontinuous frequency bands. apparatus.   The said control signal is comprised so that it may notify about whether it has the capability to transmit an uplink data signal and an uplink control signal simultaneously in the allocated discontinuous frequency band. The base station apparatus as described in. A user apparatus that wirelessly communicates with a base station apparatus in a mobile communication system,
A transmission unit configured to transmit a control signal to notify whether the base station apparatus has the ability to simultaneously transmit uplink signals in the allocated discontinuous frequency band;
The user apparatus is configured so that the control signal is notified for each operation band.   The user apparatus according to claim 4, wherein the control signal is configured to notify whether or not the control signal has an ability to simultaneously transmit an uplink data signal in an allocated discontinuous frequency band. .   The said control signal is comprised so that it may notify about whether it has the capability to transmit an uplink data signal and an uplink control signal simultaneously in the allocated discontinuous frequency band, It is characterized by the above-mentioned. A user device according to 1.

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